mirror of https://github.com/stella-emu/stella.git
Changed the font handling in the SDL OpenGL port. Previously, all 256
characters were stored in one texture, and pieces of that were carved out when a particular character was needed. That approach left visual artifacts in GL_LINEAR mode because of the way OpenGL divides up textures (clamped to [0,1]). The new approach is to use 256 8x8 textures, and draw them separately. It actually makes the drawText() and drawChar() methods much shorter. This may be slightly slower than before, but since large numbers of characters are only ever drawn when needed (versus at the current framerate), I don't think the speed difference will be noticed. git-svn-id: svn://svn.code.sf.net/p/stella/code/trunk@203 8b62c5a3-ac7e-4cc8-8f21-d9a121418aba
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stephena
parent
34addb87c6
commit
505a38057d
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@ -13,7 +13,7 @@
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// See the file "license" for information on usage and redistribution of
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// this file, and for a DISCLAIMER OF ALL WARRANTIES.
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//
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// $Id: FrameBufferGL.cxx,v 1.2 2003-11-09 23:53:20 stephena Exp $
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// $Id: FrameBufferGL.cxx,v 1.3 2003-11-12 15:12:06 stephena Exp $
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//============================================================================
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#include <SDL.h>
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@ -38,6 +38,9 @@ FrameBufferGL::~FrameBufferGL()
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{
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if(myTexture)
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SDL_FreeSurface(myTexture);
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glDeleteTextures(1, &myTextureID);
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glDeleteTextures(256, myFontTextureID);
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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@ -243,7 +246,6 @@ void FrameBufferGL::drawMediaSource() // FIXME - maybe less copying can be done?
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glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, myTexture->w, myTexture->h,
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GL_RGBA, GL_UNSIGNED_BYTE, myTexture->pixels);
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glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
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glColor3f(0.0, 0.0, 0.0);
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glBegin(GL_QUADS);
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glTexCoord2f(myTexCoord[0], myTexCoord[1]); glVertex2i(0, 0);
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@ -285,26 +287,10 @@ void FrameBufferGL::drawBoundedBox(uInt32 x, uInt32 y, uInt32 w, uInt32 h)
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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void FrameBufferGL::drawText(uInt32 xorig, uInt32 yorig, const string& message)
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void FrameBufferGL::drawText(uInt32 x, uInt32 y, const string& message)
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{
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glBindTexture(GL_TEXTURE_2D, myFontTextureID);
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glEnable(GL_BLEND);
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glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_BLEND);
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// We place the loop here to avoid multiple calls to glBegin/glEnd
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glBegin(GL_QUADS);
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for(uInt32 i = 0; i < message.length(); i++)
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{
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uInt32 x = xorig + i*8;
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uInt32 y = yorig;
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uInt8 c = message[i];
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glTexCoord2f(myFontCoord[c].minX, myFontCoord[c].minY); glVertex2i(x, y );
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glTexCoord2f(myFontCoord[c].maxX, myFontCoord[c].minY); glVertex2i(x+8, y );
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glTexCoord2f(myFontCoord[c].maxX, myFontCoord[c].maxY); glVertex2i(x+8, y+8);
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glTexCoord2f(myFontCoord[c].minX, myFontCoord[c].maxY); glVertex2i(x, y+8);
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}
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glEnd();
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drawChar(x + i*8, y, (uInt32) message[i]);
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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@ -313,14 +299,14 @@ void FrameBufferGL::drawChar(uInt32 x, uInt32 y, uInt32 c)
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if(c >= 256 )
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return;
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glBindTexture(GL_TEXTURE_2D, myFontTextureID);
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glBindTexture(GL_TEXTURE_2D, myFontTextureID[c]);
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glEnable(GL_BLEND);
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glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_BLEND);
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glBegin(GL_QUADS);
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glTexCoord2f(myFontCoord[c].minX, myFontCoord[c].minY); glVertex2i(x, y );
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glTexCoord2f(myFontCoord[c].maxX, myFontCoord[c].minY); glVertex2i(x+8, y );
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glTexCoord2f(myFontCoord[c].maxX, myFontCoord[c].maxY); glVertex2i(x+8, y+8);
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glTexCoord2f(myFontCoord[c].minX, myFontCoord[c].maxY); glVertex2i(x, y+8);
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glTexCoord2f(0, 0); glVertex2i(x, y );
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glTexCoord2f(1, 0); glVertex2i(x+8, y );
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glTexCoord2f(1, 1); glVertex2i(x+8, y+8);
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glTexCoord2f(0, 1); glVertex2i(x, y+8);
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glEnd();
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}
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@ -364,15 +350,16 @@ bool FrameBufferGL::createTextures()
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glGenTextures(1, &myTextureID);
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glBindTexture(GL_TEXTURE_2D, myTextureID);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, param);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, param);
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glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE,
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myTexture->pixels);
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// Now create the font texture. There are 256 fonts of 8x8 pixels.
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// These will be stored in a texture of size 256x64, which is 32 characters
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// per line, and 8 lines.
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SDL_Surface* fontTexture = SDL_CreateRGBSurface(SDL_SWSURFACE, 256, 64, 32,
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// Now create the font textures. There are 256 fonts of 8x8 pixels.
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// These will be stored in 256 textures of size 8x8.
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SDL_Surface* fontTexture = SDL_CreateRGBSurface(SDL_SWSURFACE, 8, 8, 32,
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#if SDL_BYTEORDER == SDL_LIL_ENDIAN
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0x000000FF, 0x0000FF00, 0x00FF0000, 0xFF000000);
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#else
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@ -382,52 +369,41 @@ bool FrameBufferGL::createTextures()
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if(fontTexture == NULL)
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return false;
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// First clear the texture
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SDL_Rect tmp;
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tmp.x = 0; tmp.y = 0; tmp.w = 256; tmp.h = 64;
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SDL_FillRect(fontTexture, &tmp,
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SDL_MapRGBA(fontTexture->format, 0xff, 0xff, 0xff, 0x0));
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// Create a texture for each character
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glGenTextures(256, myFontTextureID);
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// Now fill the texture with font data
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for(uInt32 lines = 0; lines < 8; lines++)
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for(uInt32 c = 0; c < 256; c++)
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{
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for(uInt32 x = lines*32; x < (lines+1)*32; x++)
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// First clear the texture
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SDL_Rect tmp;
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tmp.x = 0; tmp.y = 0; tmp.w = 8; tmp.h = 8;
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SDL_FillRect(fontTexture, &tmp,
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SDL_MapRGBA(fontTexture->format, 0xff, 0xff, 0xff, 0x0));
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// Now fill the texture with font data
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for(uInt32 y = 0; y < 8; y++)
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{
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for(uInt32 y = 0; y < 8; y++)
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for(uInt32 x = 0; x < 8; x++)
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{
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for(uInt32 z = 0; z < 8; z++)
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if((ourFontData[(c << 3) + y] >> x) & 1)
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{
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if((ourFontData[(x << 3) + y] >> z) & 1)
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{
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tmp.x = ((x-lines*32)<<3) + z;
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tmp.y = y + lines*8;
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tmp.w = tmp.h = 1;
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SDL_FillRect(fontTexture, &tmp,
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SDL_MapRGBA(fontTexture->format, 0x10, 0x10, 0x10, 0xff));
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}
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tmp.x = x;
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tmp.y = y;
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tmp.w = tmp.h = 1;
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SDL_FillRect(fontTexture, &tmp,
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SDL_MapRGBA(fontTexture->format, 0x10, 0x10, 0x10, 0xff));
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}
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}
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}
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}
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// Generate the character coordinates
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for(uInt32 i = 0; i < 256; i++)
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{
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uInt32 row = i / 32;
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uInt32 col = i - (row*32);
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myFontCoord[i].minX = (GLfloat) (col*8) / 256;
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myFontCoord[i].maxX = (GLfloat) (col*8+8) / 256;
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myFontCoord[i].minY = (GLfloat) (row*8) / 64;
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myFontCoord[i].maxY = (GLfloat) (row*8+8) / 64;
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}
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glGenTextures(1, &myFontTextureID);
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glBindTexture(GL_TEXTURE_2D, myFontTextureID);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, param);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, param);
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glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 64, 0, GL_RGBA, GL_UNSIGNED_BYTE,
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glBindTexture(GL_TEXTURE_2D, myFontTextureID[c]);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, param);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, param);
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glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 8, 8, 0, GL_RGBA, GL_UNSIGNED_BYTE,
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fontTexture->pixels);
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}
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SDL_FreeSurface(fontTexture);
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@ -13,7 +13,7 @@
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// See the file "license" for information on usage and redistribution of
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// this file, and for a DISCLAIMER OF ALL WARRANTIES.
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//
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// $Id: FrameBufferGL.hxx,v 1.2 2003-11-09 23:53:20 stephena Exp $
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// $Id: FrameBufferGL.hxx,v 1.3 2003-11-12 15:12:06 stephena Exp $
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//============================================================================
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#ifndef FRAMEBUFFER_GL_HXX
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@ -34,7 +34,7 @@ class MediaSource;
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This class implements an SDL OpenGL framebuffer.
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@author Stephen Anthony
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@version $Id: FrameBufferGL.hxx,v 1.2 2003-11-09 23:53:20 stephena Exp $
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@version $Id: FrameBufferGL.hxx,v 1.3 2003-11-12 15:12:06 stephena Exp $
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*/
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class FrameBufferGL : public FrameBufferSDL
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{
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@ -141,8 +141,8 @@ class FrameBufferGL : public FrameBufferSDL
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// OpenGL texture coordinates for the main surface
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GLfloat myTexCoord[4];
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// The OpenGL font texture handle
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GLuint myFontTextureID;
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// The OpenGL font texture handles (one for each character)
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GLuint myFontTextureID[256];
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// Structure to hold a characters coordinates
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struct Coordinates
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